Seeing pictures of those 10000+ GPU nightmares doesn't instill visions of decentralization, quite the opposite actually.
Massive farms exist... so what. You're looking at it the wrong way.
I can buy miner-grade GPUs from dozens of outlets in my own country. Even from a real shop in town if I can be bothered.
Something like 25% of Steam's userbase have a mining capable machine. There are 24 million copies of 'PlayerUnknown's Battlegrounds' sold. Each of those copies belongs to one person with a mining capable machine.
How many people in the world own ASICS? How many shops in the world sell them? GPU mining gear is available through the same channels as enthusiast PC gear. It's a different world.
And since everyone knows about GPU mining now, you can bet that many gamers are evolving into cryptominers.
The potential for decentralised mining is so much greater with GPUs than ASICS.